Part of the code is based on the work done by Oskari Saarenmaa <os@ohmu.fi>,which was used to support the clickpad found on ASUS UX21/31 Ultrabook.On the other hand, the FSP found on UX21/31 doesn't have hardware capabilityregister other than PnP ID, which means that we'll have to figure out analternative approach to identify such pad correctly; otherwise, blindlyadding INPUT_PROP_BUTTONPAD property may compatability issues amongstexisting FSPs.